Trends in Rates of ASIA Impairment Scale Conversion in Traumatic Complete Spinal Cord Injury

Area of Science:

• Neurology
• Rehabilitation Medicine
• Clinical Research

Background:

• Spinal cord injury (SCI) classification using the American Spinal Injury Association (ASIA) Impairment Scale (AIS) is crucial for prognosis.
• Recent data suggest higher conversion rates of AIS grades, particularly in complete SCI.
• Understanding trends in neurological recovery is vital for patient care and research.

Purpose of the Study:

• To examine the rate of conversion from complete to incomplete spinal cord injury (SCI) over time.
• To identify demographic and injury-related factors influencing conversion rates.
• To assess trends specifically for tetraplegia and paraplegia.

Main Methods:

• Analysis of a National SCI Database cohort (1995-2015) of individuals aged 16+ with complete SCI.
• Grouping subjects into 3-year intervals to assess temporal trends in conversion.
• Logistic regression used to identify factors associated with conversion (age, sex, etiology, injury level).

Main Results:

• A significant increasing trend in conversion rates was observed across all groups (p < 0.01).
• Tetraplegia showed the most dramatic increase in conversion to incomplete (17.6% to 50%) and motor incomplete (9.4% to 28.1%) injury.
• Factors associated with increased odds of conversion included later year of injury, tetraplegia level, non-violent etiology, and older age.

Conclusions:

• Conversion rates from complete to incomplete and motor incomplete SCI are rising, especially in tetraplegia.
• These findings have significant implications for the design of acute clinical trials.
• The increasing conversion rates necessitate re-evaluation of early prognostication strategies post-SCI.